1. Field of the Invention
The invention relates generally to a method of manufacturing a copper wiring in a semiconductor device. More particularly, the present invention relates to a method of manufacturing a copper wiring in a semiconductor device capable of not only realizing reappearance of copper deposition process but also obtaining a thin copper film of a good film quality, by establishing the technology of metal organic chemical vapor deposition (MOCVD) process using 1,1,1,5,5,5-hexafluoro-2,4-pentadionato (3,3-dimethyl-1-butene)-copper(I) (hereinafter called xe2x80x9c(hfac)Cu(DMB)xe2x80x9d compound as a copper precursor.
2. Description of the Prior Art
As the semiconductor industry has moved toward ultra large-scale integration (ULSI), the geometry of devices has been continuously reduced to a sub-half-micron area while the circuit density in view of improvement of performance and reliability has increased. In order to meet these needs, in forming a metal wiring in a semiconductor device, a thin copper film can increase reliability of a semiconductor device due to a high electro-migration (EM) in copper film since it has a higher melting point than aluminum. Also, thin copper film can increase the signal transfer speed due to its low resistivity. Therefore, thin copper film has been employed as a useful interconnection material for integrated circuits.
In a method of manufacturing a copper wiring, a copper deposition process is useful for realizing higher-speed devices and higher-integration devices. The process employs various deposition methods such as a physical vapor deposition (PVD) method, an electroplating method, an electroless-plating method, a metal organic chemical vapor deposition (MOCVD) method. Of these copper deposition technologies, as the copper deposition by MOCVD method is significantly affected by a copper precursor, a copper precursor must be developed which can be easily deposited. Also, a delivery system capable of safely carrying this copper precursor must be necessarily developed.
Copper deposition by MOCVD method may employ a liquid delivery system (hereinafter called xe2x80x9cLDSxe2x80x9d) of a bubbler scheme, an LDS, such as a direct liquid injection (hereinafter called xe2x80x9cDLIxe2x80x9d) or an LDS, such as a control evaporation mixer (hereinafter called xe2x80x9cCEMxe2x80x9d). In addition, it may employ various LDSs, such as an LDS having a vaporizer of an orifice scheme or a spray scheme. Copper is deposited by dissolving compounds including a copper metal called a precursor in these LDSs. The copper precursor for use in MOCVD includes CuII compounds, such as a 1,1,1,5, 5,5 hexafluoro-2,4-pentadionato-copper(II);Cu(hfac)2 compounds having a low vapor pressure. After that, CuI compounds have been developed which have a faster deposition speed due to high vapor pressure, compared to CuII compounds, thus allowing a thin copper film of a high purity to be deposited at low temperatures of 150 to 250xc2x0 C.
Among CuI compounds developed so far, 1,1,1, 5,5,5-hexafluoro-2, 4-pentadionato (trimethylvinylsilane)-copper(I) (hereinafter called xe2x80x9c(hfac)Cu(TMVS)xe2x80x9d) is a representative copper precursor for use in MOCVD. The compound is widely used since it exists at the liquid state at room temperature and allows a thin copper film of high purity to be deposited at a low temperature.
Even with these advantages, however, the (hfac)Cu(TMVS) compound has a problem in that it is degraded at high temperature and there is a difficulty in reappearance of the process when used in the process of manufacturing semiconductor devices. Also, though the vapor pressure of the (hfac)Cu(TMVS) compound is high among various precursors developed so far, it is rather low in securing appearance in a conventional LDS. Thus, there is a problem in securing reappearance as far as a new LDS capable of safely delivering a precursor. In addition, the (hfac)Cu(TMVS) has a problem that it must be kept at constant temperature since the difference between its vaporization temperature and its condensation temperature is narrow.
In order to solve problems associated with (hfac)Cu(TMVS), (hfac)Cu(DMB) has been developed as a precursor. (hfac)Cu(DMB) is a new compound which has been developed using 3,3-dimethyl-1-butene (hereinafter called xe2x80x9cDMBxe2x80x9d) as a Lewis base ligand. Since the DBM, having a low molecular weight and a high vapor pressure, is used as a Lewis base ligand instead of methyl group of TMVS, it has a higher vapor pressure than (hfac)Cu(TMVS). Therefore, the (hfac)Cu(DMB) compound is the most advantageous precursor since it can significantly improve a low deposition speed, which is one of the greatest problems in the MOCVD Cu precursor. However, the technology of MOCVD process using a (hfac)Cu(DMB) has not been established in a conventional LDS, nor commercialized.
The present invention provides a method of manufacturing a copper wiring in a semiconductor device capable of not only realizing reappearance of a copper deposition process but also obtaining a thin copper film having good film quality, by forming a chemical enhancer layer at the contact hole and the bottom of the trench and then selectively forming copper, using the technology of metal organic chemical vapor deposition (MOCVD) process using (hfac)Cu(DMB) compound as a copper precursor, without developing a new LDS.
A method of manufacturing a copper wiring in a semiconductor device according to the present invention comprises the steps of, after patterning a given region of an interlayer insulating film formed on a semiconductor substrate to form a damascene pattern, performing a cleaning process; forming a diffusion prevention film on the entire structure including the damascene pattern; forming a chemical enhancer layer on the surface of the diffusion prevention film; removing the chemical enhancer on the remaining portions except for the bottom portion of the damascene pattern, by performing immersion wet cleaning process and warm annealing process; forming a copper layer so that the damascene pattern can be filled; and polishing the copper layer to form a copper wiring.